This invention relates to a system for controlling torque through a planetary gear system. More specifically, the invention relates to the use of an oil pump combined with a planetary gear system to control the input and output torques of the system.
In all-wheel drive or four-wheel drive vehicles, one set of wheels is directly connected to the power source through a transmission, an axle, and a series of shafts. The other set of wheels can be connected to the power source through a center differential, a coupling, or an active clutch. Typically, the function of the center differential is to regulate the proportion of power that is transmitted between the front and rear sets of wheels, thereby controlling vehicle traction and cornering characteristics.
Brakes, motors, and electric generators have been combined with planetary and differential systems to control wheel torque in automobiles. Many current systems regulate torque transfer by controlling the drag between plates in a fluid-filled clutch. The use of a clutch to transfer torque is expensive to implement, however, and the operation of the clutch generates a high amount of friction that dissipates a substantial amount of the torque being transferred.
The invention provides a more efficient and less expensive system to control torque. This is accomplished with a pump combined with a planetary gear system. The pump comprises an inlet port and an outlet port for a fluid, a cover member, and a piston, which acts as the end member of the pump. An actuator is attached to the piston. The actuator moves the piston between a first and second position relative to the pump. A controller is coupled to the actuator. The controller positions the actuator in response to control signals.
Another embodiment of this invention is a method of regulating torque in a planetary gear system. First, pump pressure is increased by sealing a pump with a reciprocable piston via an actuator. Torque is then transferred through a planetary system by a sun gear coupled to the pump. The torque can then be controlled by positioning the reciprocable piston with an actuator.
Other systems, methods, features, and advantages of the invention will become apparent to one skilled in the art upon examination of the following figures and detailed description. All such additional systems, methods, features, and advantages are intended to be included within this description, within the scope of the invention, and protected by the accompanying claims.